I'm still working through the noise in the Jeep. At this point, all 4 CV axles were replaced (and I got nicely ripped-off in the process...) and the noise is still there. The noise sounds like it's coming from a rotating component. There is now a banging noise when going from drive to reverse. I put the Patriot on ramps and found rotating play movement at the rear differential flange (where the rear U-joint bolts onto it) of about about 1/2"- 3/4" if I grab the driveshaft and twist it. I'm not too familiar with differentials and don't know if that's too much. Can the rear differential be the culprit?
I would be concerned about a 1/2" to 3/4" of free play on the pinion shaft.
There was a several year run where the pinion nut could loosen up and allow a lot of slop between the ring and pinion gears. When the nut loosened, the pinion would sink back into the axle assembly. When it gets loose enough, it will bind on the ring gear and start breaking off teeth, which turns into a real mess real fast.
Pull the driveshaft off the the rear yoke, and see if the pinion can move side to side, up or down, or in and out. Might put a socket on the pinion nut to see if it turns easily without moving the yoke. If that is OK, I think I would pull the cover off the diff.
